From: Tracey Emery <tracey@traceyemery.net>
Subject: Re: let 'got branch' switch and update the work tree
To: gameoftrees@openbsd.org
Date: Mon, 24 Feb 2020 07:55:45 -0700

On Mon, Feb 24, 2020 at 03:41:02PM +0100, Stefan Sperling wrote:
> I have sometimes found myself creating a new branch and committing
> to the older branch I was on, with the sequence:
> 
> 	got br new
> 	got ci
> 
> With the diff below, the above 'got ci' would go to the new branch
> because in addition to creating the new branch in the repository
> the work tree will be switched and updated to this branch.
> 
> So the above sequence is now equivalent to:
> 
> 	got br new
> 	got up -b new
> 	got ci
> 

Yes please. I've done this far too many times when in a hurry to try a
small change and commit to the master branch instead. Ok.

> The downside is that 'got branch' could leave merge conflicts behind
> if the work tree contains local changes, especially when the -c option
> is used to create a branch based off an older commit.
> So I am adding a new -n option to 'got branch' which prevents a switch
> and update of the work tree, if desired.
> 
> I hope people will have a worse time when they forget to run 'update -b'
> before a commit than when they forget to pass the -n option to 'got branch'.
> 
> Of course, nothing changes if 'got branch' is run outside of a work tree,
> such as in the Git repository itself.
> 
> ok?
> 
> diff 98dc66a432acfcf22aa25d814ef09fa117e20a1b /home/stsp/src/got
> blob - 501781dfaf2488dd5255b6fe6d01f4c22c9693f0
> file + got/got.1
> --- got/got.1
> +++ got/got.1
> @@ -532,8 +532,8 @@ which must be an existing reference.
>  Care should be taken not to create loops between references when
>  this option is used.
>  .El
> -.It Cm branch Oo Fl c Ar commit Oc Oo Fl r Ar repository-path Oc Oo Fl l Oc Oo Fl d Ar name Oc Op Ar name
> -Manage branches in a repository.
> +.It Cm branch Oo Fl c Ar commit Oc Oo Fl r Ar repository-path Oc Oo Fl l Oc Oo Fl d Ar name Oc Oo Fl n Oc Op Ar name
> +Create, list, or delete branches.
>  .Pp
>  Branches are managed via references which live in the
>  .Dq refs/heads/
> @@ -544,6 +544,7 @@ command operates on references in this namespace only.
>  .Pp
>  If invoked in a work tree without any arguments, print the name of the
>  work tree's current branch.
> +.Pp
>  If a
>  .Ar name
>  argument is passed, attempt to create a branch reference with the given name.
> @@ -551,6 +552,22 @@ By default the new branch reference will point at the 
>  work tree's current branch if invoked in a work tree, and otherwise to a commit
>  resolved via the repository's HEAD reference.
>  .Pp
> +If invoked in a work tree, once the branch was created successfully
> +switch the work tree's head reference to the newly created branch and
> +update files across the entire work tree, just like
> +.Cm got update -b Ar name
> +would do.
> +Show the status of each affected file, using the following status codes:
> +.Bl -column YXZ description
> +.It U Ta file was updated and contained no local changes
> +.It G Ta file was updated and local changes were merged cleanly
> +.It C Ta file was updated and conflicts occurred during merge
> +.It D Ta file was deleted
> +.It A Ta new file was added
> +.It \(a~ Ta versioned file is obstructed by a non-regular file
> +.It ! Ta a missing versioned file was restored
> +.El
> +.Pp
>  The options for
>  .Cm got branch
>  are as follows:
> @@ -583,6 +600,8 @@ Only the branch reference is deleted.
>  Any commit, tree, and blob objects belonging to the branch
>  remain in the repository and may be removed separately with
>  Git's garbage collector.
> +.It Fl n
> +Do not switch and update the work tree after creating a new branch.
>  .El
>  .It Cm br
>  Short alias for
> blob - 0b384fd1f5315c96063e7c187ccbcbd0c571dc12
> file + got/got.c
> --- got/got.c
> +++ got/got.c
> @@ -3284,8 +3284,8 @@ __dead static void
>  usage_branch(void)
>  {
>  	fprintf(stderr,
> -	    "usage: %s branch [-c commit] [-r repository] [-l] | -d name | "
> -	    "[name]\n", getprogname());
> +	    "usage: %s branch [-c commit] [-d] [-r repository] [-l] [-n] "
> +	        "[name]\n", getprogname());
>  	exit(1);
>  }
>  
> @@ -3470,10 +3470,17 @@ cmd_branch(int argc, char *argv[])
>  	struct got_repository *repo = NULL;
>  	struct got_worktree *worktree = NULL;
>  	char *cwd = NULL, *repo_path = NULL;
> -	int ch, do_list = 0, do_show = 0;
> +	int ch, do_list = 0, do_show = 0, do_update = 1;
>  	const char *delref = NULL, *commit_id_arg = NULL;
> +	struct got_reference *ref = NULL;
> +	struct got_pathlist_head paths;
> +	struct got_pathlist_entry *pe;
> +	struct got_object_id *commit_id = NULL;
> +	char *commit_id_str = NULL;
>  
> -	while ((ch = getopt(argc, argv, "c:d:r:l")) != -1) {
> +	TAILQ_INIT(&paths);
> +
> +	while ((ch = getopt(argc, argv, "c:d:r:ln")) != -1) {
>  		switch (ch) {
>  		case 'c':
>  			commit_id_arg = optarg;
> @@ -3491,6 +3498,9 @@ cmd_branch(int argc, char *argv[])
>  		case 'l':
>  			do_list = 1;
>  			break;
> +		case 'n':
> +			do_update = 0;
> +			break;
>  		default:
>  			usage_branch();
>  			/* NOTREACHED */
> @@ -3570,7 +3580,6 @@ cmd_branch(int argc, char *argv[])
>  	else if (delref)
>  		error = delete_branch(repo, worktree, delref);
>  	else {
> -		struct got_object_id *commit_id;
>  		if (commit_id_arg == NULL)
>  			commit_id_arg = worktree ?
>  			    got_worktree_get_head_ref_name(worktree) :
> @@ -3580,15 +3589,59 @@ cmd_branch(int argc, char *argv[])
>  		if (error)
>  			goto done;
>  		error = add_branch(repo, argv[0], commit_id);
> -		free(commit_id);
> +		if (error)
> +			goto done;
> +		if (worktree && do_update) {
> +			int did_something = 0;
> +			char *branch_refname = NULL;
> +
> +			error = got_object_id_str(&commit_id_str, commit_id);
> +			if (error)
> +				goto done;
> +			error = get_worktree_paths_from_argv(&paths, 0, NULL,
> +			    worktree);
> +			if (error)
> +				goto done;
> +			if (asprintf(&branch_refname, "refs/heads/%s", argv[0])
> +			    == -1) {
> +				error = got_error_from_errno("asprintf");
> +				goto done;
> +			}
> +			error = got_ref_open(&ref, repo, branch_refname, 0);
> +			free(branch_refname);
> +			if (error)
> +				goto done;
> +			error = switch_head_ref(ref, commit_id, worktree,
> +			    repo);
> +			if (error)
> +				goto done;
> +			error = got_worktree_set_base_commit_id(worktree, repo,
> +			    commit_id);
> +			if (error)
> +				goto done;
> +			error = got_worktree_checkout_files(worktree, &paths,
> +			    repo, update_progress, &did_something,
> +			    check_cancelled, NULL);
> +			if (error)
> +				goto done;
> +			if (did_something)
> +				printf("Updated to commit %s\n", commit_id_str);
> +		}
>  	}
>  done:
> +	if (ref)
> +		got_ref_close(ref);
>  	if (repo)
>  		got_repo_close(repo);
>  	if (worktree)
>  		got_worktree_close(worktree);
>  	free(cwd);
>  	free(repo_path);
> +	free(commit_id);
> +	free(commit_id_str);
> +	TAILQ_FOREACH(pe, &paths, entry)
> +		free((char *)pe->path);
> +	got_pathlist_free(&paths);
>  	return error;
>  }
>  
> blob - 2a7d11efbed29670e6e1ba9db1450f174a74d399
> file + regress/cmdline/branch.sh
> --- regress/cmdline/branch.sh
> +++ regress/cmdline/branch.sh
> @@ -18,6 +18,7 @@
>  
>  function test_branch_create {
>  	local testroot=`test_init branch_create`
> +	local commit_id0=`git_show_head $testroot/repo`
>  
>  	# Create a branch based on repository's HEAD reference
>  	got branch -r $testroot/repo newbranch
> @@ -58,7 +59,7 @@ function test_branch_create {
>  	fi
>  
>  	# Create a branch based on the work tree's branch
> -	(cd $testroot/wt && got branch anotherbranch)
> +	(cd $testroot/wt && got branch -n anotherbranch)
>  	ret="$?"
>  	if [ "$ret" != "0" ]; then
>  		test_done "$testroot" "$ret"
> @@ -74,7 +75,7 @@ function test_branch_create {
>  	fi
>  
>  	# Create a branch based on another specific branch
> -	(cd $testroot/wt && got branch -c master yetanotherbranch)
> +	(cd $testroot/wt && got branch -n -c master yetanotherbranch)
>  	ret="$?"
>  	if [ "$ret" != "0" ]; then
>  		test_done "$testroot" "$ret"
> @@ -103,6 +104,24 @@ function test_branch_create {
>  	ret="$?"
>  	if [ "$ret" != "0" ]; then
>  		echo "git checkout command failed unexpectedly"
> +		test_done "$testroot" "$ret"
> +		return 1
> +	fi
> +
> +	# Create a branch and let the work tree be updated to it
> +	(cd $testroot/wt && got branch -c $commit_id0 updatebranch \
> +		> $testroot/stdout)
> +
> +	echo -n "Switching work tree from refs/heads/newbranch to " \
> +		> $testroot/stdout.expected
> +	echo "refs/heads/updatebranch" >> $testroot/stdout.expected
> +	echo "U  gamma/delta" >> $testroot/stdout.expected
> +	echo "Updated to commit $commit_id0" >> $testroot/stdout.expected
> +
> +	cmp -s $testroot/stdout.expected $testroot/stdout
> +	ret="$?"
> +	if [ "$ret" != "0" ]; then
> +		diff -u $testroot/stdout.expected $testroot/stdout
>  	fi
>  	test_done "$testroot" "$ret"
>  }
> blob - 3c441f126f81e96af27255bfe1ac35115c1b2673
> file + regress/cmdline/rebase.sh
> --- regress/cmdline/rebase.sh
> +++ regress/cmdline/rebase.sh
> @@ -741,7 +741,7 @@ function test_rebase_no_commits_to_rebase {
>  		return 1
>  	fi
>  
> -	(cd $testroot/wt && got branch newbranch)
> +	(cd $testroot/wt && got branch -n newbranch)
>  
>  	echo "modified alpha on master" > $testroot/wt/alpha
>  	(cd $testroot/wt && got commit -m 'test rebase_no_commits_to_rebase' \
> @@ -848,7 +848,7 @@ function test_rebase_forward {
>  		return 1
>  	fi
>  
> -	(cd $testroot/wt && got branch > $testroot/stdout)
> +	(cd $testroot/wt && got branch -n > $testroot/stdout)
>  	echo "master" > $testroot/stdout.expected
>  	cmp -s $testroot/stdout.expected $testroot/stdout
>  	ret="$?"

-- 

Tracey Emery